Shelter



FIG. 1 is a perspective view from the front of a shelter embodying my new design;

FIG. 2 is an elevational view from the side of the shelter of FIG. 1;

FIG. 3 is an elevational view from the rear of the shelter of FIG. 1; and

FIG. 4 is a bottom plan view of the shelter of FIG. 1. 

The ornamental design for a shelter, substantially as shown and described. 